Liquid water likely exists on the surface of Mars and below the icy crusts of Europa, Enceladus, and Titan. Pluto, Ceres, and Ganymede also show evidence of liquid water at or near the surface. Quantitative solute analyses would provide critical data needed to understand geochemical conditions throughout our solar system, including potential habitability of planetary bodies. We have developed and tested a Raman spectroscopic method for measuring perchlorate and sulfate in brines and dilute waters that utilizes simple Raman peak height ratios rather than peak area ratios. Ratios of the target anion and OH- bending water peaks yield linear fits with positive slopes and r² values >0.99. Calibration fits for each solute–brine combination and ultrapure water yield similar linear equations, suggesting this method can detect and quantitatively measure solutes in complex aqueous solutions. No sample preparation or physical contact with the sample is required. Therefore, this method can be employed without contaminating the fluid or the spacecraft.

中文翻译：

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使用拉曼光谱法测量行星盐水中的高氯酸盐和硫酸盐

液态水很可能存在于火星表面，并且在欧罗巴，土卫二和土卫六的冰壳下方。冥王星，谷神星和木卫三也显示出表面或附近有液态水的迹象。定量溶质分析将提供了解整个太阳系中地球化学条件所需的关键数据，包括行星体的潜在可居住性。我们已经开发并测试了拉曼光谱法，该方法利用简单的拉曼峰高比而不是峰面积比来测量盐水和稀水中的高氯酸盐和硫酸盐。目标阴离子与OH弯曲水峰之比得出具有正斜率和r ^2的线性拟合值> 0.99。每种溶质-盐水组合的校准拟合和超纯水产生相似的线性方程，这表明该方法可以检测和定量测量复杂水溶液中的溶质。无需样品制备或与样品物理接触。因此，可以采用这种方法而不会污染流体或航天器。